Citizen Bat Monitors: Turning Up the Volume On Silence

The deadly bat disease called white nose syndrome was found in Wisconsin earlier this year. That’s bad news for bats, but it hasn’t stopped the Department of Natural Resources from investing in bat monitoring efforts. In fact, biologists say collecting data on bats is more important than ever.

Credit Natalie Jablonski / WXPR News

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At nightfall on the end of a pier in Eagle River, DNR Biologist Paul White is standing with his arm outstretched, rubbing his fingers together.

The air is filled with electronic chirps that sound like they belong in a video game, but they're actually the sounds of bats calling and feeding. Humans typically can’t hear bats communicating…but tonight we’re armed with the bat detector. It’s a handheld ultrasound device that translates the high pitched bat calls into something human ears can hear.

Credit Matthew Rethaber / WXPR News

White explains that by rubbing his fingers together, he’s getting their attention. The bats can sense the movement and they’re coming to check it out. White says there are about 15 of them, but it feels like 50…they’re flashing and swooping past our faces.

Bats can be difficult to study, because they’re fast flyers and they’re only out at night. But biologists have been learning more about Wisconsin’s bat populations thanks to the work of volunteers, who since 2007 have been conducting hundreds of short bat surveys. That means going out after dark on foot, by car or by kayak – and gathering data with one of the handheld bat detectors and a GPS device.

“All of a sudden we’re drawing pictures around the state of where certain bats are occurring," White explains. "And we have 7 different species; I can say with complete confidence that a lot of information that we have now is because of citizen scientists. They’re going out there looking for bats, they’re able to carve out that range of where bats are located, how bats are moving."

Each species of bat has a unique call length and frequency, and the bat detectors can tell the difference.

The surveys can’t tell us exactly how many bats are in each location; but it can give a relative abundance: a sense of where the hotspots are. That’s especially important now that the deadly fungal disease white nose syndrome has arrived in Wisconsin, threatening to wipe out the state’s four cave bat species. The state’s winter bat population is estimated at up to half a million, making it one of the largest hibernating populations in the Midwest. The disease’s looming threat is one reason Quita Sheehan got involved.

“It’s kind of scary," she said. "I think it’s neat that everybody who’s volunteering is trying to do their part to help the DNR and others get more data. Who knows what’s going to happen.”

Collecting data may not seem like much of a defense against the powerful disease that has already killed millions of bats in the U.S. and Canada, but it's one of the few tools managers have right now. The DNR is already restricting access and requiring decontamination procedures for people who want to visit certain caves. But there's little that managers can do to control the activity of bats themselves.